What is most worthwhile?
Based on this overview, the ETH researchers subsequently assessed the economic viability of various technology combinations. They reproduced the systems in a computer model and calculated their capital value. This value includes all costs and income during a system’s service life.
It is evident that just the addition of a photovoltaic plant together with a conversion technology such as a heat pump can produce energy more cost-effectively than the still widespread infrastructure with oil heating systems and electricity from the public electricity grid. The calculations for one specific example – a small settlement with three single-family homes, three multi-family homes and a small office building – revealed that this combination comprising photovoltaics and a heat pump is the cheapest variant.
If, however, a storage technology – a battery, a thermal storage device or a hydrogen storage device – is added to such a system, the energy supply becomes slightly more expensive once more. Hydrogen storage devices, in particular, see costs rocket. This especially impacts stand-alone systems that are cut off from the electricity grid and thus reliant on such storage technologies: energy storage becomes two to three times more expensive. “However, this is likely to change in future”, says Hoffmann. Among other reasons, this is because the costs for the technologies are likely to fall in future, while prices for electricity, oil and natural gas are set to increase slightly.